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How To Clean A Car Engine

How To Clean A Car Engine

A clean engine can make it easier to conduct repairs and maintenance. It is best to clean your engine before washing your car, so you can ensure you wash and rinse off any degreaser that may reach painted areas. Cleaning the engine regularly will prevent rust from developing. Road grime and salt are the biggest culprits in developing rust, so rinsing the engine bay will prolong the life of your vehicle’s engine.


  1. Protecting and Preparing Your Dirty Engine Before you begin cleaning the engine, remove any leaves, grass, twigs or other debris from the engine bay. Debris can cause engine fires if left to sit on the engine or electrical system. It is common for pine needles to collect at the bottom of the windshield and then fall into the engine bay.

  2. Protect the Electrical System of the Car Different components of the electrical system, including the battery, need to be properly covered to prevent any water damage whilst cleaning

  3. Disconnect the Battery Do not spray water directly into your engine bay as it may cause some of the electrical components to arc, blowing fuses or causing other damage. Prevent this by loosening the bolt on the negative terminal on the battery and sliding the ground cable off the terminal.

  4. Cover Exposed Wiring and Electronics While your engine is fairly waterproof, wrapping plastic around electrical components can offer you a higher degree of safety. Cover the spark plugs inlets, loose wires and the distributor cap.

  5. Let the Engine Run for Five Minutes Grease on the engine will be much easier to remove when heated. This will allow the engine to get to normal operating temperature and loosen any stuck on grime.

  6. Apply Engine Degreaser There are many brands of engine degreaser to choose from. Spray the degreaser on the engine from the bottom up, as this will ensure total coverage. Ensure you read the instructions on the spray can for best results.

  7. Avoid Getting any Degreaser on Painted areas Engine degreaser can remove clear coat from paint, so be careful not to overspray while covering the engine.

  8. Allow the Degreaser to soak in for 3 to 5 minutes Engine degreaser works by eating away at the stuck on grime on the engine.

  9. Use a stiff bristled brush to scrub stuck on grime With the degreaser still soaking on the engine, use a stiff bristled or steel toothed brush to scrub away at any large deposits of grease, burned oil, or grime.

  10. Rinse the engine with a garden hose Do not use a high pressure hose to rinse the engine as it may disconnect wires or penetrate the plastic you used to cover electronics. A regular garden hose with the nozzle set to stream will rinse the engine effectively and remove most of the grime.

  11. Wash the Car Once you have rinsed the engine off, you should begin washing your car immediately. This will ensure you clean any engine degreaser off of painted components before it has the chance to cause damage.